PROJECT SUMMARY Intensive lifestyle interventions (diet and exercise) are the mainstay of treatment in prediabetes. Despite their efficacy, diabetes incidence is rising, and thus there is a critical need for additional strategies to prevent diabetes and to reduce its cardiovascular complications. Sleep apnea is a treatable disorder that has been strongly associated with cardiometabolic disease. Continuous positive airway pressure (CPAP) is the recommended treatment for those who are diagnosed with sleep apnea. However, about 80% of patients who have sleep apnea remain undiagnosed, and thus not receive CPAP treatment. To date, not a single clinical trial investigating the effects of lifestyle interventions on cardiometabolic risk in prediabetes assessed for sleep apnea or included an intervention to treat sleep apnea. Despite high prevalence of sleep apnea in prediabetes, the vast majority of patients are not diagnosed due to lack of high level evidence to indicate that treatment specifically improves diabetes and cardiovascular outcomes, which are the primary treatment objectives of specialists caring for this high-risk population. Moreover, due to insufficient evidence from rigorous and well-powered randomized controlled trials, the U.S. Preventive Health Services Task Force recommended against general screening for sleep apnea. Notably, not a single randomized controlled CPAP trial assessing cardiometabolic outcomes utilized a technology-supported intervention to promote adherence, a key limitation in prior studies. Our proposed randomized clinical trial will fill these critical knowledge gaps and address a focused, novel and clinically relevant question. We will determine, for the first time, whether adding CPAP treatment to a lifestyle intervention improves cardiometabolic outcomes beyond that achieved with lifestyle alone (i.e. current standard of care) in prediabetes. Overweight and obese adults who have prediabetes and sleep apnea will be randomly assigned to lifestyle alone or lifestyle plus CPAP. We will obtain the same metabolic and cardiovascular assessments at baseline and after 6-months of intervention. Our specific aims are to test the hypothesis that a combined intervention (lifestyle plus CPAP) will lead to greater improvements in glucose levels, insulin sensitivity and beta cell function (Aim 1), and blood pressure and lipid profile (Aim2), as compared to lifestyle alone. To maximize intervention success and minimize subject burden, we propose a highly efficient, cost effective technology-supported approach for lifestyle intervention and CPAP treatment, which will allow real-time, objective monitoring of individuals in their habitual environment and delivering timely feedback to attain goals. To date, no prior study has implemented such a technology-supported intervention in people with prediabetes and sleep apnea. An added benefit of CPAP on cardiometabolic outcomes will strongly support routine screening for and treatment of sleep apnea in prediabetes and will encourage those prescribing CPAP to routinely implement intensive lifestyle modifications as part of treatment package for sleep apnea. Our trial will address a major gap in randomized clinical trials on the impact of sleep apnea treatment on glucose metabolism, and thus inform evidence-based clinical decision making.